Method for reducing welding hollows of LTCC substrate and metal base plate and LTCC substrate structure

A metal base plate and substrate technology, applied in the direction of electrical connection of printed components, printed circuit components, etc., can solve the problems of blocking organic substances and gas escape channels, reducing welding area and grounding area, affecting welding strength and grounding performance, etc. To achieve the effect of reducing the maximum void area, reducing the formation of voids, and reducing the void area

Active Publication Date: 2014-10-08
NO 43 INST OF CHINA ELECTRONICS TECH GRP CETC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the spacing between the bulk metallization areas is too large, although it is conducive to the escape of flux and gas during welding, the too wide spacing reduces the welding area and grounding area, which affects the welding strength and grounding performance
If the spacing between the block metallized areas is too small, there will be alignment problems

Method used

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  • Method for reducing welding hollows of LTCC substrate and metal base plate and LTCC substrate structure
  • Method for reducing welding hollows of LTCC substrate and metal base plate and LTCC substrate structure

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0029] Example 1

[0030] (1) Take 70wt% of zinc borophosphate glass powder (composition of ZnO: 40wt%, B 2 O 3 :10wt%, P 2 O 5 : 50wt%, softening point 410-440℃), add 30wt% of a mixture of ethyl cellulose and terpineol (in the mixture, ethyl cellulose accounts for 8wt%, terpineol accounts for 92wt%), mix and grind It is adjusted into paste form to obtain solder mask paste that can be used for printing. The solder resist paste is printed on the thick film metallization layer on the surface of the LTCC substrate through a screen plate with grid lines made, and the line width of the grid lines is 0.2mm and the line spacing is 3mm. After the grid lines are heated at 130-150°C for 8-10 minutes and dried, they are put into a sintering furnace for sintering at a sintering temperature of 550°C. After sintering, the solder mask grid lines are firmly attached to the metallization layer of the substrate.

[0031] (2) The required low-temperature solder paste Sn62Pb36Ag2 is printed on the...

Example Embodiment

[0033] Example 2

[0034] (1) Take 65wt% of the zinc borophosphate glass powder described in Example 1 and 8wt% of the inorganic additive Al 2 O 3 , Grind it evenly, then add a mixture of 27wt% ethyl cellulose and terpineol (in the mixture, ethyl cellulose accounts for 5wt%, terpineol accounts for 95wt%), and mix and grind into slurry form , Which can be used for printing solder paste. The solder resist paste is printed on the thick metallization layer on the surface of the LTCC substrate through a screen plate with grid lines. The line width of the grid lines is 0.25 mm and the line spacing is 2.5 mm. After the grid lines are dried at 130-150°C for 8-10 minutes, they are put into a sintering furnace for sintering at a sintering temperature of 600°C. After sintering, the solder mask grid lines are firmly attached to the metallization layer of the substrate.

[0035] (2) Print the required medium temperature solder paste Sn96.5Ag3.5 on the surface of the metallization layer of th...

Example Embodiment

[0037] Example 3

[0038] Step (1) Take 65wt% of the zinc borophosphate glass powder described in Example 1, and add 35wt% of a mixture of polyvinyl alcohol and butyl carbitol acetate (in the mixture, polyvinyl alcohol accounts for 4wt%, butyl carbitol Alcohol acetate accounts for 96wt%), and other processes are the same as in Example 1.

[0039] X-ray inspection found that the welding void ratio between the substrate and the metal bottom plate is about 17%, the maximum void is less than 3% of the welding area, and the welding area is evenly distributed.

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Abstract

The invention discloses a method for reducing welding hollows of an LTCC substrate and a metal base plate. The method comprises the following steps: presetting criss-cross resistance welding grid lines on a metalization layer of the surface of the substrate, and then welding the LTCC substrate and the metal base plate by adopting welding paste. As the grid lines are printed on the metalization layer of the welding surface of the LTCC substrate, discharge of fluxes and gas can be increased during welding of the LTCC substrate and the metal base plate, the formation of the hollows is reduced, and the voidage is reduced. As the grid lines are printed on the metalization layer of the welding surface of the LTCC substrate, more fluxes and gas can be discharged during welding, the accumulation of fluxes and gas is prevented, the welding area is increased, and the area of the biggest hollow is reduced. The design of multi-layer substrates and high-density grounding through holes does not need to be changed, many times of printing alignment for thickening of the rectangular-block metalization layer is avoided, and the grid lines are directly printed on the large-area metalization layer of the substrate. The printing is simple, the grid lines are clear and reliable, and the discharge channel of the fluxes can be ensured.

Description

technical field [0001] The invention relates to a method for reducing welding voids between an LTCC substrate and a metal bottom plate and a novel LTCC substrate obtained by the method. Background technique [0002] With the development of microelectronics technology, low-temperature co-fired ceramics (LTCC) for multilayer circuit wiring have been more and more widely used in the miniaturization and high-density integration of modules or systems, especially in microwave / radio frequency, LTCC It has unique advantages as a substrate for transceiver components. In use, LTCC ceramic substrates are often welded to heat sinks or metal shells (both called metal bottom plates). At present, the welding of the LTCC ceramic substrate and the metal base plate is generally sintered on the surface of the substrate with a weldable thick-film metallization layer (soldering layer), and then printed or coated with tin solder paste (such as low-temperature solder paste Sn62Pb36Ag2, medium-te...

Claims

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Application Information

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IPC IPC(8): H05K1/11
Inventor 李建辉吴建利戴端
Owner NO 43 INST OF CHINA ELECTRONICS TECH GRP CETC
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